The research program conducted under this grant relates to chemical regulation of the synthesis, metabolism and function of heme and cytochrome P-450. Lead is utilized as a prototype environmental pollutant which inhibits these processes; polychlorinated biphenyls are studies as prototype environmental agents which stimulate these processes. Studies in man and in various laboratory preparations are conducted to determine the nature and extent of biological impact of these environmental chemicals on heme parameters. BIBLIOGRAPIC REFERENCES: Kappas, A., H.L. Bradlow, D.R. Bickers and A.P. Alvares: Induction of a deficiency of steroid Delta 4-5 alpha-reductase activity in liver by a porphyrinogenic drug. Journal of Clinical Investigation, 59: 159-164, 1977. Maines, M.D. and A. Kappas: Enzymatic oxidation of cobalt protoporphyrin IX. Observations on the mechanism of heme oxygenase action. Biochemistry, 16: 419-423, 1977.